Publications associées à Regiodivergent Cyclobutanone Cleavage: Switching Selectivity with Different Lewis Acids

Engineering Frustrated Lewis Pair Active Sites in Porous Organic Scaffolds for Catalytic CO2 Hydrogenation

Anne-Clémence Corminboeuf, Jacob Terence Blaskovits, Shubhajit Das, Rubén Laplaza Solanas

Frustrated Lewis pairs (FLPs), featuring reactive combinations of Lewis acids and Lewis bases, have been utilized for myriad metal-free homogeneous catalytic processes. Immobilizing the active Lewis sites to a solid support, especially to porous scaffolds, ...

Amer Chemical Soc2024

Expanding computational biochemistry towards complex and non-natural compounds

Anastasia Sveshnikova

In the beginning was the metabolism. The biochemical processes that make life possible transformed the soup of chemicals into the life on Earth we know today. Since then, living organisms have evolved, and life on Earth has become more complex. Living orga ...

EPFL2023

Recent Advances in Group 14 and 15 Lewis Acids for Frustrated Lewis Pair Chemistry

Shubhajit Das

Frustrated Lewis pairs (FLP) which rely on the cooperative action of Lewis acids and Lewis bases, played a prominent role in the advancement of main-group catalysis. While the early days of FLP chemistry witnessed the dominance of boranes, there is a growi ...

WILEY-V C H VERLAG GMBH2022

Water Orientation at the Anatase TiO2 Nanoparticle Interface: A Probe of Surface pKa Values

Arianna Marchioro, Marie Bischoff

The acid-base properties of surfaces significantly influence catalytic and (photo)electrochemical processes. Estimation of acid dissociation constants (pKa values) for colloids is commonly performed through electroanalytical techniques or spectroscopic met ...

AMER CHEMICAL SOC2022

How Robust Is the Reversible Steric Shielding Strategy for Photoswitchable Organocatalysts?

Anne-Clémence Corminboeuf, Raimon Fabregat I De Aguilar-Amat, Veronika Juraskova, Théo Pierre Jaffrelot Inizan, Simone Gallarati

A highly appealing strategy to modulate a catalyst's activity and/or selectivity in a dynamic and noninvasive way is to incorporate a photoresponsive unit into a catalytically competent molecule. However, the description of the photoinduced conformational ...

AMER CHEMICAL SOC2022

Activation of aminocyclopropanes via radical intermediates

Jérôme Waser, Mingming Wang

Aminocyclopropanes are versatile building blocks for accessing high value-added nitrogen-containing products. To control ring-opening promoted by ring strain, the Lewis acid activation of donor-acceptor substituted systems is now well established. Over the ...

Royal Society of Chemistry2022

Investigating Tetrel-Based Neutral Frustrated Lewis Pairs for Hydrogen Activation

Shubhajit Das

Tetrel Lewis acids are a prospective alternative to commonly employed neutral boranes in frustrated Lewis pair (FLP) chemistry. While cationic tetrylium Lewis acids, being isolobal and iso(valence)electronic, are a natural replacement to boranes, neutral t ...

AMER CHEMICAL SOC2021

Bronsted and Lewis acid adducts of triazenes

Kay Severin, Rosario Scopelliti, Farzaneh Fadaei Tirani, Abdusalom Suleymanov, Frederick Mark Chadwick, Iris Roswitha Landman

The synthetic utility of triazenes rests on the fact that the triazene function can be cleaved by BrOnsted or Lewis acids, liberating diazonium compounds. However, the preferred coordination site of the acid is still a matter of debate. We have analyzed tr ...

2020

SET processes in Lewis acid–base reactions: the tritylation of N-heterocyclic carbenes

Andrzej Sienkiewicz, Kay Severin, Rosario Scopelliti, Cristian Pezzato, Farzaneh Fadaei Tirani, Zhaowen Dong

Reactions between N-heterocyclic carbenes (NHCs) and the trityl cation, [Ph3C]+, give covalent adducts of type [NHC–CPh3]+ and/or [NHC–C6H5–CPh2]+. EPR spectroscopy, UV-Vis analyses, and trapping experiments imply that adduct formation involves carbene rad ...

2020

Ruthenium on phosphorous-modified alumina as an effective and stable catalyst for catalytic transfer hydrogenation of furfural

Gaël Peng, Thibault Xavier Florian Fovanna, Oliver Kröcher, Davide Ferri

Supported ruthenium was used in the liquid phase catalytic transfer hydrogenation of furfural. To improve the stability of Ru against leaching, phosphorous was introduced on a Ru/Al2O3 based catalyst upon impregnation with ammonium hypophosphite followed b ...

2020

Metal organic frameworks and methods for using thereof

Paul Joseph Dyson, Fatmah Ebrahim, Berend Smit, Kyriakos Stylianou, Serhii Shyshkanov, Ngoc Tú Nguyên

The invention features metal-organic frameworks (MOFs) having a crystalline lattice comprising metallic nodes and organic ligands, wherein each organic ligand comprises a Lewis acidic or basic centre bound to N conjugated systems, wherein N is comprised be ...

2020

Advances in heterogeneous catalysis for the synthesis of polyoxymethylene dimethyl ethers

Christophe Jean Baranowski

Our society is engaged in a major shift towards more sustainable industries. The required transition from fossils to renewable resources with low greenhouse gas emission is specifically challenging in the transportation sector where high thermal efficiency ...

EPFL2020

Role of glutathione S-transferases and the mercapturic acid pathway in the biotransformation potential of two zebrafish (Danio rerio) test systems: early life stages and PAC2 cells

Alena Tierbach

Zebrafish (Danio rerio) early life stages provide an important model for chemical risk assessment due to their genetic similarity to humans and the availability of well-established high-throughput techniques. Cells isolated from zebrafish conserve all thes ...

EPFL2020

All-in-One Deposition to Synergistically Manipulate Perovskite Growth for High-Performance Solar Cell

Frank Nüesch, Jie Wu, Hui Zhang, Wei Huang

Nonradiative recombination losses originating from crystallographic distortions and issues occurring upon interface formation are detrimental for the photovoltaic performance of perovskite solar cells. Herein, we incorporated a series of carbamide molecule ...

2020

The acidity of atmospheric particles and clouds

Tao Wang, Athanasios Nenes

Acidity, defined as pH, is a central component of aqueous chemistry. In the atmosphere, the acidity of condensed phases (aerosol particles, cloud water, and fog droplets) governs the phase partitioning of semivolatile gases such as HNO3, NH3, HCl, and orga ...

Copernicus Publications2020

Synthetic methodologies for C-C and C-N bond formation involving alkyl radicals

Guido Barzanò

C-C and C-N bonds are some of the most common structures in molecules ranging from drugs to catalysts and to food additives. Many coupling reactions were developed to form these types of bonds with excellent selectivity and good performance. Still, the syn ...

EPFL2020

Nature of Synergy between Bronsted and Lewis Acid Sites in Sn-Beta Zeolites for Polyoxymethylene Dimethyl Ethers Synthesis

Christophe Jean Baranowski, Oliver Kröcher, Alimohammad Bahmanpour

The role of Lewis and Bronsted acid sites and their potential synergy remains ambiguous for the production of polyoxymethylene dimethyl ethers (OME), which are suitable as a Diesel substitute. Here, this synergistic effect was investigated by using a serie ...

WILEY-V C H VERLAG GMBH2019

Production, characterization and upgrading of biomass-derived acetal-stabilized carbohydrates

Ydna Marie Questell-Santiago

Biomass is an attractive source of renewable carbon-based fuels and chemicals. Multiple research efforts are centered around integrated biorefineries, where all fractions of biomass are converted to fuels or chemical products. These efforts are focused aro ...

EPFL2019

Effects of water-soluble organic carbon on aerosol pH

Athanasios Nenes

Water-soluble organic carbon (WSOC) is a ubiquitous and significant fraction of fine particulate matter. Despite advances in aerosol thermodynamic equilibrium models, there is limited understanding on the comprehensive impacts of WSOC on aerosol acidity (p ...

Copernicus GmbH2019

Evidence for a dual mechanism in the TiO2/CuxO photocatalyst during the degradation of sulfamethazine under solar or visible light: Critical issues

Juan Kiwi, César Pulgarin, Sami Rtimi, Jiajie Yu

This study presents the photocatalytic degradation of sulfamethazine (SMT) on TiO2/CuxO nanotubes (NTs) by a differentiated mechanism under low intensity solar light and indoor visible light irradiation. In the presence of TiO2/CuxO nanotubes, the SMT-degr ...

ELSEVIER SCIENCE SA2019